Cross-linked Carbon Nanofibers Research Articles

Electrochemiluminescence Sensor based on Electrospun Crosslinked Carbon Nanofibers for the Detection of Difenidol Hydrochloride.

Cross-linked porous carbon nanofibers (CNF) were successfully prepared by electrospinning and high-temperature carbonization. Polyacrylonitrile (PAN) as the carbon source and genipin as the cross-linking agent were used to prepare cross-linked porous carbon nanofibers (CNF). The field emission scanning electron microscopy (SEM), transmission electron microscope (TEM), automatic specific surface and porosity analyzer Brunner Emmet Teller (BET), X-ray diffraction (XRD), and a laser confocal microspectroscope (Raman, XploRA PLUS, Horiba) were used to characterize the materials. The CNF suspension was dropped on the surface of the bare glassy carbon electrode by the drip coating method to obtain a CNF-modified electrode. Cyclic voltammetry was used to study the electrochemiluminescence behavior of difenidol hydrochloride on CNF-modified glassy carbon electrode (Glassy Carbon Electrode, GCE). Herein, we synthesised a kind of crosslinked carbon nanofibers and designed a novel ECL biosensor. Under the optimal conditions, the concentration of difenidol hydrochloride exhibited a linear relationship with the peak current in the range of 8.0×10-8 to 1.0×10-4 mol/L, with the correlation coefficient of R2=0.997, and a low detection limit (1.2×10-8 mol/L). Difenidol hydrochloride in difenidol hydrochloride tablets was tested, and the recovery rate of sample addition was estimated to be 83.17%-92.17%, and the RSD value to be <5.0%. The designed platform exhibited excellent analytical performance for difenidol hydrochloride determination.

Flexible and cross-linked carbon nanofibers based on coal liquefaction residue for high rate supercapacitors

Free-standing electrospun carbon nanofibers nonwovens (CNF) with an outstanding cross-linked architecture can be successfully achieved via a simple and practicable strategy by combining electrospinning, stabilization and carbonization. In this study, the hybrids of asphaltene extracted from coal residue liquefaction, polyacrylonitril and terephthalic acid are used as precursors. Due to the synergistic effect of efficient cross-linked structures and short charge transfer channels, flexible cross-linked asphaltene-based CNF (CLACF), as the binder-free supercapacitor electrode, exhibits a high capacity of 225 F g−1 at 0.2 A g−1 and an outstanding rate capability of 148 F g−1 at 100 A g−1. The developed symmetrical supercapacitor based on CLACF has a maximum energy density of 4.20 Wh kg−1 with a power density of 1.22 kW kg−1. It also has excellent cyclic stability with 97.3% capacitance retention after 10,000 cycles at 2 A g−1.

Uniform coverage of high-loading sulfur on cross-linked carbon nanofibers for high reaction kinetics in Li–S batteries with low electrolyte/sulfur ratio

Aggregation of high loading sulfur on host materials at low carbon/sulfur ratio results in the limited S↔Li2S reaction kinetics, which is a bottleneck for the development of lithium sulfur batteries with high energy densities.

Fast-Charging Nonaqueous Potassium-Ion Batteries Enabled by Rational Construction of Oxygen-Rich Porous Nanofiber Anodes.

Practical applications of carbon anodes in high-power potassium-ion batteries (PIBs) were hampered by their limited rate properties, due to the sluggish K+ transport kinetics in the bulk. Constructing convenient ion/electron transfer channels in the electrode is of great importance to realize fast charge/discharge rates. Here, cross-linked porous carbon nanofibers (inner porous carbon nanotubes and outer soft carbon layer) modified with oxygen-containing functional groups were well designed as anodes to realize robust de-/potassiation kinetics. The novel anode delivered excellent rate capabilities (107 mAh g-1 at 20 A g-1 and 78 mAh g-1 at 40 A g-1) and superior cycling stability (76% capacity retention after 14,000 cycles at 2 A g-1). In situ XRD measurement, in situ Raman spectra, and galvanostatic intermittent titration verified its surface-dominated potassium storage behavior with fast de-/potassiation kinetics, excellent reversibility, and rapid ion/electron transport. Moreover, theoretical investigation revealed that the carboxyl groups in the carbon offered additional capacitive adsorption sites for K+, thus significantly enhancing the reversible capacity. Surprisingly, a full cell using the anode and perylene-3,4,9,10-tetracarboxylic dianhydride cathode achieved an outstanding power density of 23,750 W kg-1 and superior fast charge/slow discharge performance.

Facile Preparation of Low-Cost and Cross-Linked Carbon Nanofibers Derived from PAN/PMMA/Lignin as Supercapacitor Electrodes

To develop economical and high-performance water electrolyte supercapacitor electrodes, low-cost and cross-linked carbon nanofibers (CNFs) were prepared with an electrospinning method by using PAN,...

Flexible Cross-Linked Electrospun Carbon Nanofiber Mats Derived from Pitch as Dual-Functional Materials for Supercapacitors

Freestanding and binder-free electrospun carbon nanofiber mats with a cross-linked structure (CLCF) were fabricated by using pitch as the precursor. The cross-linked structure can be tuned easily b...

Engineering Bifunctional Host Materials of Sulfur and Lithium-Metal Based on Nitrogen-Enriched Polyacrylonitrile for Li-S Batteries.

Lithium-sulfur batteries (LSBs) still suffer from the shuttle effect on the cathode and the lithium dendrite on the anode. Herein, polyacrylonitrile (PAN) is developed into a bifunctional host material to simultaneously address the challenges faced on both the sulfur cathode and lithium anode in LSBs. For the sulfur cathode, PAN is bonded with sulfur to produce sulfurized PAN (SPAN) to avoid the shuttle effect. The SPAN is accommodated into a conductive 3D CNTs-wrapped carbon foam to prepare a self-supporting cathode, which improves the electronic and ionic conductivity, and buffers the volume expansion. Thereby, it delivers reversible capacity, superb rate capability, and outstanding cycling stability. For the Li-metal anode, PAN aerogel is carbonized to give macroporous N-doped cross-linked carbon nanofiber that behaves as a lithiophilic host to regulate Li plating and suppress the growth of Li dendrite. Combining the improvements for both the cathode and anode realizes a remarkable long-term cyclability (765 mAh g-1 after 300 cycles) in a full cell. It provides new opportunity to propel the practical application of advanced LSBs.

Amine-Terminated Highly Cross-Linked Polyphosphazene-Functionalized Carbon Nanotube-Reinforced Lignin-Based Electrospun Carbon Nanofibers

To improve the mechanical properties of lignin-based carbon nanofibers, the amine-terminated highly cross-linked polyphosphazene-functionalized carbon nanotubes (PZAA@CNTs) were successfully synthe...

Free-standing cross-linked activated carbon nanofibers with nitrogen functionality for high-performance supercapacitors

Flexible, heteroatoms-rich activated carbon nanofibers with fascinating cross-linked architectures are successfully gained in a facile and controllable way via electrospinning polyacrylonitrile (PAN) /dicyandiamide (DICY) composite nanofibers followed by carbonation and a CO2 activation process. The unique inter-bonded structures and heteroatoms contents could be easily controlled by adjusting the preoxidation temperature applied in the calcining procedure and the addition of DICY. Significantly, the resultant samples display hierarchical pores with micro/meso/macropores, abundant N, O species doped and unique fiber–fiber interconnections, which considerably boost the electrochemical properties. As an electrode material, the activated N-doped cross-linked carbon nanofibers (ANCLCNFs) show a high capacitance of 323 F g−1 with a current density of 0.5 A g−1, excellent rate capacity (230.1 F g−1 at 20 A g−1) and long-term duration (over 95% after 10000 cycles). Furthermore, the symmetrical supercapacitor delivers a maximum energy density of 14.3 Wh kg−1 at a power density of 162.5 W kg−1.

AC-Filtering Supercapacitors Based on Edge Oriented Vertical Graphene and Cross-Linked Carbon Nanofiber

There is strong interest in developing high-frequency (HF) supercapacitors or electrochemical capacitors (ECs), which can work at the hundreds to kilo hertz range for line-frequency alternating current (AC) filtering in the substitution of bulky aluminum electrolytic capacitors, with broad applications in the power and electronic fields. Although great progress has been achieved in the studies of electrode materials for ECs, most of them are not suitable to work in this high frequency range because of the slow electrochemical processes involved. Edge-oriented vertical graphene (VG) networks on 3D scaffolds have a unique structure that offers straightforward pore configuration, reasonable surface area, and high electronic conductivity, thus allowing the fabrication of HF-ECs. Comparatively, highly conductive freestanding cross-linked carbon nanofibers (CCNFs), derived from bacterial cellulose in a rapid plasma pyrolysis process, can also provide a large surface area but free of rate-limiting micropores, and are another good candidate for HF-ECs. In this mini review, advances in these fields are summarized, with emphasis on our recent contributions in the study of these materials and their electrochemical properties including preliminary demonstrations of HF-ECs for AC line filtering and pulse power storage applications.

Simultaneous cross-linking and pore-forming electrospun carbon nanofibers towards high capacitive performance

Large effective surface area and high electrical conductivity are critical for the high-performance carbon-based electrode materials for supercapacitors. Herein, three-dimensional (3D) cross-linked nitrogen-enriched porous carbon nanofibers (C-CNFs) are facilely prepared by electrospinning of polyacrylonitrile/zinc chloride (PAN/ZnCl2) precursor, preoxidation and carbonization of the electrospun composite nanofibers. The ZnCl2 additive makes effects of both cross-linking and pore-forming electrospun carbon nanofibers simultaneously. The as-prepared C-CNFs exhibits a good rate capability of about 60% with current densities ranging from 1 to 60 A g−1, excellent cycling stability of 97.3% over 60,000 cycles in alkaline electrolyte, and high specific capacitance of 214 F g−1 at 1.0 A g−1 in acidic electrolyte, all of which are significantly superior to the non-cross-linked carbon nanofibers. The significant enhancement of capacitive performance of C-CNFs can be attributed the synergistic effect of its enlarged specific surface area for more charge accumulation and cross-linked architecture that enable the electrons to fast transfer throughout the fibrous membrane. Moreover, the 3D cross-linked carbon nanofiber networks is expected to be a building block of composite electrodes fabrication for the promising applications in other systems that involve a continuous pathway for electron transport, such as the metal ion batteries and catalysis.

Fibrous Bio-Carbon Foams: A New Material for Lithium-Ion Hybrid Supercapacitors with Ultrahigh Integrated Energy/Power Density and Ultralong Cycle Life

A naturally fibrous carbon foam is fabricated by employing fish bones as raw materials. Differing to carbon foams in previous reports, numerous unwoven and cross-linked carbon nanofibers were found to construct the whole foam, exhibiting a hierarchical porosity with interconnected channels and multisize pores. In the meantime, on the basis of the rich organic–inorganic components of fish bones, an N-S-P-O codoping was achieved in carbon foams. Benefiting from the synergistic effects of hierarchically porous fibrous foam and multiple heteroatom doping, the as-obtained samples were employed both as anode and cathode materials in lithium ion hybrid supercapacitors (LIHC), which delivered a superior energy density of 131 Wh kg–1 in 0–4.0 V. Significantly, at an impressive power density of 62000 W kg–1, the energy density of this device can still reach an ultrahigh energy density of 72 Wh kg–1, which presents a state of the art supercapacitors. More importantly, continuously being charged/discharged at a high ...

Preparation of Si-doped and cross linked carbon nanofibers via electrospinning and their supercapacitive properties

In this work, Si-doped cross linked carbon nanofibers (Si/CNF) were prepared by electrospinning polyacrylonitrile (PAN) solutions containing polyhedral oligomeric silsesquioxane (POSS) as Si source, followed by thermal treatments. Scanning electron microscope (SEM) observations showed the smooth surfaces of pure PAN nanofibers, while PAN/POSS nanofibers with obviously rough or porous surfaces were obtained with relatively high POSS content. X-ray diffraction (XRD) identified the presence of POSS in the composite nanofibers. After thermal treatments, cross linked Si/CNFs with various morphologies were obtained. Energy-dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the successful incorporation of Si into CNFs. Raman spectra suggested the degree of carbon ordering of Si/CNFs reduced slightly when compared with pure CNF. The obtained nanofibers exhibited typical performances of electric double-layer capacitors (EDLC). The specific capacitance of Si/CNF showed a moderate increase with POSS content and reached a maximum of 175 F/g at 1 A/g with PAN:POSS equal to 100:5. Meanwhile Si/CNFs exhibited excellent cycling stability after 1000 cycles. The influence of POSS on the capacitive performance might be attributed to the combined effects of evolution of morphology, conductivity and surface properties of Si/CNFs.

Carbon Nanofiber Aerogel Converted from Bacterial Cellulose for Kilohertz AC-Supercapacitors

ABSTRACTCompact-size kilohertz (kHz) AC-supercapacitors are being pursued for ripple current filtering and pulsed energy storage. However, their development is limited by a small areal capacitance density due to very thin electrode used for meeting frequency requirement. In our work, crosslinked carbon nanofiber aerogel (CCNFA) was investigated as freestanding electrode for kHz AC-supercapacitors with an areal capacitance density as large as 4.5 mF cm-2 at 120 Hz, 5-10 times larger than most reports. The CCNFA was obtained in a rapid plasma carbonization process of bacterial cellulose. The fabrication route adopted here is simple and straightforward, and the produced CCNFA electrode was found to be very suitable for high-frequency AC-supercapacitors. The operating voltage range of CCNFA based AC-supercapacitors can be expanded to 3 V by utilizing an organic electrolyte. In addition to AC-Supercapacitor performance, the morphology and material properties of bacterial cellulose aerogel and CCNFA were also reported.

Crosslinked carbon nanofiber films with hierarchical pores as flexible electrodes for high performance supercapacitors

Flexible, cross-linked carbon nanofibers (CNFs) film with hierarchical micro-meso-macro-porous structure is prepared by carbonization of the elestrospun polyacrylonitrile (PAN)/NaN3 composite nanofiber mats. The gas liberation of NaN3 during the carbonization is responsible for the tuning of both specific surface area and the pore size distribution. In addition, the exothermal decomposition of NaN3 at the heating stage of carbonization leads to the melting of the PAN/NaN3 composite fibers, resulting in a cross-linked CNF structure. The CNF film with 5wt% NaN3 carbonized at 900°C (CNF-5-900) shows a high specific capacitance of 222.92Fg−1, nearly twice as high as that of the CNF film without NaN3 (CNF-0-900). It also shows an excellent capacitance retention ratio of 81.97% of its initial capacitance from 0.5A/g to 50A/g, much superior to the value of 51.02 % for CNF-0-900. Moreover, it has an excellent cycling stability with cycling retention ratio achieves 94.5% after 10,000 charge-discharge cycles. Coupled with its excellent mechanical stability (only 1.6% conductivity loss after bending of CNF-5-900 film at curvature radii (r)=2.5×10−3m for 10,000cycles) and facile fabrication process, the flexible, cross-linked CNF films with hierarchical micro-meso-macro-porous structure is a potential electrode materials and/or backbone to support other active materials for various application, including the flexible energy storage and electrocatalytic.

Bacterial cellulose derived carbon nanofiber aerogel with lithium polysulfide catholyte for lithium–sulfur batteries

Highly insulating nature of sulfur species and the shuttling effects caused by soluble lithium polysulfides have been blamed for hindering the development of lithium–sulfur (Li–S) batteries. A variety of carbonaceous materials have been investigated to ameliorate these problems by providing a conductive matrix with physical trapping and chemical binding capabilities, but inevitably resulted in typically low sulfur content in the cathode and hence low gross specific energy when considering all the active and inactive masses. A highly conductive and crosslinked matrix with superior trapping and binding capability to sulfur species but a very low mass density is essential. Herein, crosslinked carbon nanofiber aerogel (CNFA) with extremely low density, attained from pyrolysis of bacterial cellulose (BC) aerogel, was studied for sulfur cathodes. With its unique combination of several merits, in particular the capability of strong absorption of catholyte, CNFA based sulfur electrodes exhibit outstanding performance. With 75% sulfur content of the gross cathode mass, cells demonstrated an initial capacity of 1360 mA h g−1 at 0.2 C, and exhibited excellent cycling stability with 76% of the initial capacity retained after 200 cycles.

High-frequency electrochemical capacitors based on plasma pyrolyzed bacterial cellulose aerogel for current ripple filtering and pulse energy storage

There are great needs in developing compact-size kilohertz (kHz) high-frequency (HF) electrochemical capacitors (ECs) for ripple current filtering and environmental vibration energy harvesting. However, the previously demonstrated electrodes are generally limited to a very small areal capacitance density at 120Hz due to sub-μm thick electrode used for meeting frequency requirement, which renders them unsuitable for practical ECs. Here, using crosslinked carbon nanofiber aerogel, derived from rapid microwave plasma pyrolysis of bacterial cellulose that was synthesized in a fermentation process, we demonstrated kHz HF-ECs with areal capacitance density as high as 4.5mFcm−2 at 120Hz in an aqueous electrolyte. The cruciality of plasma pyrolysis on high frequency response of the derived carbon nanofiber aerogel was discussed. The electrode performance in an organic electrolyte was further studied for operation in a large potential window of more than 3V. Using such kHz HF-ECs, we further demonstrated their applications in rapid pulse energy storage for vibrational energy harvesting, as well as in ripple current filtering for AC/DC conversion. The promising results suggest this technology has great potential for developing practical compact HF-ECs in substitution of electrolytic capacitors for several crucial applications.

Assessing the Internal Structure of Cross-Linked Carbon Nanofibers by Chemical Methods

The structure of cross-linked carbon nanofibers of DNIPRO industrial carbon fabric produced by pyrolysis of hydrated cellulose is assessed, and their oxidation temperature (Tox = 923 ± 10 K) is found. Fractionated extraction of carbon (as CO2) in a purified oxygen flow is measured by coulometry of the extracted CO2 versus time at Tox. A selective chemical procedure for qualitative identification and determination of cross-linked carbon nanofibers in carbon nanomaterials of arbitrary composition is developed for the first time.

Electrospun cross-linked carbon nanofiber films as free-standing and binder-free anodes with superior rate performance and long-term cycling stability for sodium ion storage

A novel cross-linking strategy is proposed to design electrospun carbon nanofiber films towards free-standing and binder-free electrodes for sodium-ion storage.

Facile fabrication of cross-linked carbon nanofiber via directly carbonizing electrospun polyacrylonitrile nanofiber as high performance scaffold for supercapacitors

Cross-linked carbon nanofiber (CLCNF) was successfully prepared by directly carbonizing electrospun polyacrylonitrile (PAN) nanofiber. Comparing to non-cross-linked carbon nanofiber (NCLCNF) obtained via carbonizing of pre-oxidation PAN nanofiber, CLCNF shows better conductivity owing to its cross-linked structure. Then CLCNF was used as scaffold to support polyaniline (PANi) nanorods for supercapacitor electrode material. The hierarchical CLCNF/PANi composite displays a capacity of 206Cg−1 at 0.5Ag−1 with excellent rate capability (remains 49% even at 800Ag−1), which is much higher than that of NCLCNF/PANi composite (17%). More interestingly, supercapacitor device based on CLCNF/PANi composite achieves 75.3% capacity retention after 10000 charge-discharge cycles at 10Ag−1, suggesting excellent cycle stability. All these experimental results indicate that this method for fabricating CLCNF is a substantial advancement towards the practical applications of carbon nanofiber in energy conversion and storage field.